Filling devices are used, for example, in the beverage industry for filling bottles with beverages. In the process, the bottles are usually introduced into a filler with several filling elements, where each of the filling elements comprises a filling valve, a filling tube and a return vas tube. A bottle to be filled is lifted in the filler by a lifting cylinder and pressed to the filling valve outlet of a filling element by a centering bell, whereby the filling valve is opened and the product to be filled is directed from a ring bowl into the bottle.
Usually, vacuum is applied to the ring bowl with the product to be filled. The return gas tubes of the filling elements reach into the vacuum region of the ring bowl. When the bottle is pressed against the filling valve outlet, a vacuum path from the bowl into the bottle is also opened, whereby return gas can escape from the bottle into the vacuum region of the ring bowl.
As soon as the product to be filled rises above the lower opening of the return gas tube and thereby closes the vacuum path, the filling process is stopped, the bottle is withdrawn from the filling valve, and air flowing from outside into the bottle results in the excessive filled product being sucked back into the ring bowl.
However, it is a disadvantage of these known systems that the fill height can only be changed by adjusting the height of the ring bowl or by exchanging spacers, which is complicated.
Therefore, several systems have been suggested which permit to adjust the height of the return gas tube independent of the ring bowl. However, the known systems are generally mechanically very complex.